Eraser attachment for lead pencils



April 23, 1935. w.l-:. MusGRAvE ERASER ATTACHMENT FOR LEAD PENCILS Filed April so,` 1934 @www Patented Apr. 23, 1935 i UNITED STATES PATENT OFFICE 1,998,684 EnAsEn ATTACHMENT For. LEAD rENcrLs william naw- Mumave, chingo, m. Application Api-i1 so, 1934, serial No. 123,038 3 claims. (ci. 12o-as) My invention relates to eraser attachments for ture is to provide a beveled annular shouldery or lead pencils and the like. lip protruding outwardly from the upper edge of The general object of the invention is to pro- 'the ferrule for cooperating with the aforemenvide an improved eraser lattachment which tioneclbeveled surfaceor shoulder formed on the have a much longer life than the majority of eraser. 5

' erasers now suppliedl on pencils. For example, Other objects and advantages of the invention my improved eraser supplied on the end of a will appear from the following detail description conventional wood pencil lasts substantially as of certain preferred embodiments thereof. In long as the pencil. the accompanying drawing illustrating such em- More specically, it is one of the objects of the bodiments: invention to provide an improved eraser charac- Figure 1 is an elevational view showing my imterized by a head portion which is considerably proved eraser attachment applied to a convenlarger than the diameter of the pencil, and by a tional wood pencil; shank portion which is of substantially the same Figure 2 is a fragmentary sectional view, on an diameteras that of the pencil. The relatively enlarged scale, showing one embodiment of my 15 small shank portion is receivable within a ferrule improved construction; N on the end of the pencil, by which the eraser is Figure 3 is a similar view illustrating the conattaehed to the pencil, and the relatively large struction wherein the rshank portion is made of a head portion protrudes outwardly beyond this stiier consistency of rubber and wherein this ferrule. 'I'he shank portion which extends down stiier consistency is extended up into the body 20 into the ferrule is lwaste rubber in the sense that of the enlarged head portion; it cannot be used for erasing, and by reducing Figure 4 is a similar view showing the provision this shank portion down substantially to the diof a beveled shoulder or lip on the upper end of ameter of the pencil there is effected a decided the ferrule fOr @Operating With the beveled Sursaving in the cost of these rubber erasers. Furface formed in the eraser between the shank porthermore, in one embodiment of my invention, tion and the head portion; this reduced shank portion adapts itself to at- Figure 5 1S e Similar View ShOWng a 001515191110- tachment in a conventional ferrule of substantion wherein the reenforcing features illustrated tially the same diameter from end to end therein Figures 3 and 4 are employed conjointly. of, so that the eraser is usable in conventional de- Figures 6, 7 and 3 are 'detail DerSDeCiVe VieWS 30 signs of pencils without requiring any alteration illustrating different shapes which may Abe given or change inthe size or shape of the ordinary ferthe enlarged head portion of 'the eraser. rule. The enlarged head portion affords much A conventional pencil is indicated at Il, commore rubber for erasing purposes than the con- PriSins the WOOd body Portion l2 enclosing the ventional eraser which is ordinarily or the same lead I4. This pencil may be cylindrical, hexagdiameter from endto end. It also affords alarger onal, or of any other desired shape. Afxed to area of erasing surface. Practically the entire the upper end of this pencil is a metallic ferrule body of this enlarged head portion can be used l5. The attachment may be effected in any deuntil the eraser is worn down substantially to the sired manner, represented by annular beads I6 40 small diameter shank portion, or until the eraser which are creased into the wood of the pencil, 40 is worn down to the top edge of the ferrule. and by punch pricks I1 punched into the pencil. Another object of the invention is to reenforce That portion of the ferrule projecting beyond the the eraser at the point of juncture between the body of the pencil defines a socket I8 for receivreduced shank portion and the enlarged head ing the shank portion of the eraser. VIt will be portion, where considerable'iiexing strain is borne noted that in the embodiments illustrated in 45 by--a reduced cross-section of rubber. One of Figures 2 and 3 the ferrule I5 is of substantially these reenforcing features is the provision of a the same diameter from end to end thereof, so beveled or tapered annular surface formed in the that the entire depth of the eraser receiving sockeraser at this point of juncture for distributing et I8 is of substantially the same diameter as the the flexing stresses over an appreciable length of pencil. 50 the eraser. Another reenforcing feature is that My improved eraser 2| comprises the aforeo! making the shank portion of a stiffer consistmentioned head portion 22 and shank portion 23. ency of rubber, and preferably extending this At the juncture between the head and shank there stiffer material upwardly into the body of the enis preferably formed a beveled annular surface or l larged head portion. Another reenforcing feashoulder 24. The shank portion 23 is secured 55 within the socket portion I8 of the ferrule in any suitable manner, represented by annular beads I6 and prick punchings I1' similar to those referred to above. If desired, the eraser might be cemented in the socket I8.

The provision of the tapered surface 24 reenforces the juncture between the enlarged head portion and the reduced shank portion by virtue of distributing flexing stresses, over a greater length of the rubber, rather than concentrating them substantially at the top edge of the ferrule I5. This surface may consist of a longer, more gradual taper for distributing the flexing stresses over a greater length of the rubber, if desired. Likewise, the head portion 22 may be otherwise proportioned so long as it increases the amount of rubber available for erasing purposes. exemplary proportions illustrated, the head portion aiords more than twice as much useful rubber than if it were of the same diameter as the shank portion. The embodiment of Figure 2 represents the eraser as being of the same consistency of rubber in both the head and shank portions.

In the embodiment illustrated in Figure 3, the shank portion 23 is composed of a stiil'er consistency of rubber, and, preferably, this stiifer material is extended up into the body of the head portion 22, substantially as indicated at 23a. 'Ihis stiffer consistency may be obtained by a greater proportion of abrasive material, by an increased amount of sulphur or by the use of other curing agents having this stiilening characteristic, by a longer interval of curing,by a higher curing temperature, or by any well known practice for making this portion of the rubber more resistant to tea'ring or breaking at the juncture point between the head and shank of the eraser. 'I'here is complete molecular fusion or cohesion between the rubber of the relatively stiff shank extension 23a and the rubber of the remaining head portion surrounding this shank extension, whereby there is no possibility of separation between the two. As illustrative of one method of making such an eraser, the rubber of stiffer consistency constituting theportions 23, 23a may be molded separately and partially cured before the rubber constituting the remainder of the head portion is molded and cured over the/shank extension 23a; although it will beunderstood that the entire eraser might be molded and cured as a unit. Attention is directed to the fact that by extending the shank extension 23a of relatively stiffer consistency up into the head portion 22, the eraser is materially reenforced against exing stresses adjacent to the top-edge of the ferrule I5 without reducing the amount of rubber available for erasing purposes, since the shank extension 23a aifords an effective erasing medium, being only slightly stiffer or possibly more abrasive. When employing this method of reenforclng the eraser, the head portion 22 may be extended down to a square shoulder projecting outwardly at right angles, directly above the top edge of the ferrule I5, if desired; although in the preferred embodiment using the stiffer consistency of shank portion I retain the beveled surface v24, substantially as shown.

In the embodiment illustrated in Figure 4, the ferrule I5 is formed with an outwardly diverg'ing flange or lip I5a around its upper edge. The tapered surface 24 of the eraserilts snugly against the tapered surface of this flange I5a, whereby the juncture between the head portion and shank portion is reenforced by the ferrule against iiex- IntheA ing/stresses. The provision of this tapered flange does not objectionably decrease the amount of rubber in the head portion available for erasing purposes.

The embodiment illustrated in Figure 5 combines the reenforcing features disclosed in Figures 3 and 4. The shank portion 23 is composed of rubber of a stiffer consistency, and this stiffer material is extended up into the head portion, as indicated at 23a and as previously described; and the ferrule I5 is p'rovided with the outwardly tapered lip I5a for engagement against the tapered surface' 24' of the eraser. In such a construction, the eraser is doubly reenforced against the flexing stresses at the base of the head portion.

The head portion may be given different distinctive shapes for utilitarian, ornamental or advertising purposes. For example, it may be square or cubical in outline, as illustrated in Figure 6, hexagonal or octagonal, as illustrated in Figure 7, or it may be provided with a conical tip, as illustrated in Figure 8. In any of these modied formations, reenforcement may be established between the enlarged head portion and the reduced shank portion, such as by the provision of the beveled surface 24, the extension of the shank portion 23a of stiffer consistency up into the body of the head portion, and/or the provision of the beveled ange I 5a on the ferrule.

By virtue of the reduced shank portion 23, which is of no larger diameter than that of the conventional eraser socket I8 of the ordinary pencil, each and every one of the above described embodiments of my improved eraser can be afiixed within the regular ferrule of the ordinary pencil. It will also be understood that my invention is adaptable to mechanical feed pencils, fountain pens and the like.

While I have illustrated what I regard to be the preferred embodiments of my invention, nevertheless it will be understood that such are merely exemplary and that various changes in the size, shape, proportion and minor details of construction may be made without departing from the essence of the invention.

For example, with particular reference to Figures 3 and 5, while my preferred embodiment of eraser utilizing different compositions or treatments of rubber for the head and shank portions is one wherein the shank portion 23, 23a is of a stiffer consistency than the head portion, nevertheless this'relation might be reversed or modified so that this shank portion 23, 23a would consist of extremely elastic or pliable rubber whereby to minimize the possibility of tearing or breaking from lateral iiexing at the juncture between the head and the shank. As another alternative construction, where rubber of stiITer consistency is employed in the shank portion 23, 23a, this same stiffer rubber might also be extended throughout the head portion so that the entire eraser would be of this same relatively'stiif consistency.

I claim:-

1. An article of manufacture for attachment' to a pencil, comprising a ferrule adapted to be permanently and immovably secured to one end of said pencil and being of substantially the same diameter from end to end thereof, and an eraser consisting of a shank portion of relatively small diameter and a head portion oi relatively large diameter, said shank portion being secured `within said ferrule and said head portion protruding 75 outwardly beyond said ferrule, said shank portion being composed of a stiffer consistency of rubber than said head portion, and including an extension projecting upwardly into the body of said head portion. l

2. An larticle oi manufacture for attachment to a pencil, comprising a ferrule for mounting on one end of said pencil, and an eraser consisting of a shank portion of relatively small diameter, a head portion of relatively large diameter, and a beveled annular shoulder joining said shank portion with said head portion, said shank portion being secured within said ierrule and said head portion and shoulder protruding outwardly beyond said ferrule, a stiller consistency oi rubber composing said shank portion and extending upwardly into the body of said head portion 3. An article of manufacture for attachment to a pencil, comprising a ferrule adapted to be permanently and immovably secured to one end V of said pencil and formed with an outwardly flaring annular lip at its upper edge, and an eraser consisting of a shank portion of relatively small diameter, a head portion of relatively large diameter, and a beveled annular shoulder at the juncture between said head lportion and said shank portion, said shank portion being xedly secured within said feri'ule and said shoulder abutting against said outwardly aring lip on said ferrule, said shank portion being composed of a relatively stiller consistency of rubber than the major part of said head portion, said relatively stiffer consistency of rubber extending up into said head portion and having molecular cohesion with the rubber of said head portion, and minimizing lateral exing of the eraser at the juncture' between said head portion and said shank portion.

WILLIAM EDGAR MUSGRAVE. 

